Hydrogen generation apparatus for internal combustion engines and method thereof

ABSTRACT

A system and method are provided for generating hydrogen for use with an internal combustion engine. The system includes a venturi device coupled with an exhaust stream from the internal combustion engine. The venturi device creates a gas flow through a condenser to generate reactant water. After the reactant water is polished to remove contaminants, hydrogen and oxygen are disassociated using a PEM based electrolyzer. The hydrogen gas is used by the internal combustion engine to assist in the combustion process and reduce pollutant emissions.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.10/081,666 which was filed on Feb. 22, 2002, now U.S. Pat. No.6,665,049.

FIELD OF INVENTION

This disclosure relates generally to the generation of hydrogenutilizing exhaust from and internal combustion engine, and especiallyrelates to the use of electrolysis of water for the generation of thehydrogen.

BRIEF DESCRIPTION OF RELATED ART

A typical internal combustion engine such as that generally used inautomobiles, trucks and other vehicles use hydrocarbon fuels forcombustion. Since a portion of the hydrocarbon fuel remains unburned asthe exhaust exits the engine, pollutants are generated and released tothe environment. A number of attempts have been made to increase theefficiency and completeness of combustion by utilizing catalysts andadditives which decrease the quantity of pollutants post-combustion inthe exhaust.

One additive used is the introduction of gaseous hydrogen into the fuelmixture before combustion. When mixed and combusted with the hydrocarbonfuel, the gaseous hydrogen enhances the flame velocity and permits theengine to operate with leaner fuel mixtures. Thus, hydrogen has acatalytic effect causing a more complete burn of the existing fuel andyields a reduction in exhaust emissions.

Due to the advantages of hydrogen in reducing the exhaust emissions, anumber of attempts have been made to incorporate a system with vehicles.Unfortunately, gaseous hydrogen is not readily available to the generalpublic. To overcome this lack of availability, systems using anelectrochemical cells have been proposed to provide the necessaryhydrogen.

Electrochemical cells are energy conversion devices, usually classifiedas either electrolysis cells or fuel cells. A proton exchange membraneelectrolysis cell can function as a hydrogen generator byelectrolytically decomposing water to produce hydrogen and oxygen gas,and can function as a fuel cell by electrochemically reacting hydrogenwith oxygen to generate electricity. Referring to FIG. 1, which is apartial section of a typical anode feed electrolysis cell 100, processwater 102 is fed into cell 100 on the side of an oxygen electrode(anode) 116 to form oxygen gas 104, electrons, and hydrogen ions(protons) 106. The reaction is facilitated by the positive terminal of apower source 120 electrically connected to anode 116 and the negativeterminal of power source 120 connected to a hydrogen electrode (cathode)114. The oxygen gas 104, and a portion of the process water 108, exitcell 100, while protons 106 and water 110 migrate across a protonexchange membrane 118 to cathode 114 where hydrogen gas 112 is formed.The hydrogen gas 112 and the migrated water 110 exit cell 100 from thecathode side of the cell 100.

Another typical water electrolysis cell using the same configuration asis shown in FIG. 1 is a cathode feed cell, wherein process water is fedon the side of the hydrogen electrode. A portion of the water migratesfrom the cathode across the membrane to the anode where hydrogen ionsand oxygen gas are formed due to the reaction facilitated by connectionwith a power source across the anode and cathode. A portion of theprocess water exits the cell at the cathode side without passing throughthe membrane, while oxygen gas saturated with water vapor exits the cellat the anode side.

In vehicle applications, it is necessary provide a water source togenerate the hydrogen. Prior art solutions incorporate a water reservoirthat must be periodically replenished. The disadvantage of this solutionis that it adds an additional maintenance procedure for the engineoperator.

What is needed in the art is a hydrogen generation system for use withan internal combustion engine that requires minimal maintanence and amethod for use thereof.

SUMMARY OF INVENTION

Disclosed herein are hydrogen generation systems for use with internalcombustion engines and methods for use thereof. An exemplary embodimentof the hydrogen generation system comprises: an exhaust venturi, acondenser in fluid communication with the venturi, the condenserextracting water from the exhaust stream and an electrolyzer in fluidcommunication with the condenser, the electrolyzer producing hydrogengas.

Another embodiment of the hydrogen generation system comprises: anexhaust venturi, an air inlet in fluid communication with the venturiand ambient air, a condenser in fluid communication with the venturi andthe air inlet, the condenser extracting water from the ambient air, andan electrolyzer in fluid communication with the condenser, theelectrolyzer producing hydrogen gas.

One embodiment for an internal combustion engine comprises: an internalcombustion engine, an exhaust pipe coupled to the internal combustionengine, a condenser in fluid communication with the exhaust pipe; and anelectrolyzer in fluid communication with the condenser; One embodimentfor operating a hydrogen generation system for use with an internalcombustion engine comprises: drawing exhaust gas from an exhaust pipe,condensating water from said exhaust gas, storing said water, andgenerating hydrogen from said water.

Another embodiment for operating a hydrogen generation system comprises:creating gas flow with a venturi, drawing ambient air into a condenser,condensing water from the ambient air, storing said water, andgenerating hydrogen from said water.

One embodiment for operating an internal combustion engine comprises:mixing hydrogen and hydrocarbon fuel, combusting the fuel mixture,exhausting the combusted mixture, creating gas flow with an exhaustventuri, drawing ambient air into a condenser, condensing water from theambient air, storing said water, and generating hydrogen from saidwater.

The above discussed and other features will be appreciated andunderstood by those skilled in the art from the following detaileddescription and drawings.

BRIEF DESCRIPTION OF DRAWINGS

Referring now to the drawings, which are meant to be exemplary and notlimiting, and wherein like elements are numbered alike:

FIG. 1 is a schematic diagram illustrating a prior art electrochemicalcell; and,

FIG. 2 is a schematic diagram representing a hydrogen generation systemfor use with an internal combustion engine.

DETAILED DESCRIPTION

A wide variety of applications utilize internal combustion engines toconvert hydrocarbon fuels, such as gasoline, diesel, natural gas andpropane, into mechanical energy. These include transportationapplications, such as automobiles, trucks and the like, and stationaryapplications such as electrical generators. The one problem theseapplications have in common is the pollution generated and released intothe atmosphere. Pollutants are caused by unburned or incomplete burningof the hydrocarbon fuel in the internal combustion engine. One techniqueemployed to reduce pollution emissions in the exhaust of the internalcombustion engine includes the addition of additives such as hydrogeninto the hydrocarbon fuel prior to combustion. The hydrogen increasesthe flame velocity of the fuel mixture during combustion resulting inless non-combusted hydrocarbon fuel in the exhaust stream.

A system 10 for generating hydrogen gas for use with an internalcombustion engine is shown in FIG. 2. An exhaust stream 12 from aninternal combustion engine (not shown) is routed away from enginethrough an exhaust pipe 13 in a typical manner well known in the art. Aventuri 14 is along the exhaust pipe 13. While the venturi 14 can belocated anywhere along the length of the exhaust pipe 13, it ispreferred that it is located downstream from a catalytic device (e.g. acatalytic converter) which removes many of the pollutant compounds fromthe exhaust stream 12. A tube 15 connects a condenser 18 with theexhaust pipe 13. For reasons that will be made clearer herein, it ispreferred that the tube 15 be located upstream from the venturi 14.While engine exhaust alone could be used in the system, it is preferableto provide an air inlet 16 connected to the tube 15 to provide ambientair into the system 10. With the air inlet 16 connected, the system hasthe option of using ambient air or exhaust gas to generate reactantwater. A sensor 25 such as a, dew point sensor, measures the propertiesof the ambient air. These properties may include ambient airtemperature, relative humidity and/or dew point. The sensor 25 isconnected to a control system 40 which determines which gas stream wouldrequire a minimal condenser energy. A valve 27 in response to thecontrol system 40 will activate to allow either exhaust gas or ambientair into the system 10.

The condenser 18 removes heat Q from either the engine exhaust 12 or theambient air causing water to condensate and collect in the reactantwater reservoir 22 via line 19. The condenser 18 can be of any typecapable of cooling the gas to a temperature to its dew point.Preferably, the condenser would be a conductive type cooler, such as athermo-electro or liquid refrigerant cooler capable of removing at least680 BTU/Hr of heat from the gas. Preferably the condenser has thecapacity to remove 300 to 700 BTU/hr Other types of condensers mayinclude, but are not limited to, convection type coolers such as a fansystems. Preferably, the liquid refrigerant system would be coupled avehicle air conditioning system, or the internal combustion radiator. Areturn line 26 connects the reservoir 22 with the venturi 14 via a valve20. It is preferred that the valve 20 be a solenoid valve that isactuated by a control system (not shown). A sensor 24 is also connectedto the reservoir 22 to detect and provide feedback to the system onlevel of the water in the reservoir 22.

If desired, an optional reserve line 28 and reserve reservoir 28 may beincluded to provide a backup water source during brief periods wherehumidity condensate may be unavailable. To minimize the maintenancerequirements of the reserve system, the reserve reservoir 28 may alsoperform as the storage reservoir for other devices associated with theapplication such as a windshield wiper or the engine radiator. If theassociated devices require additional compounds, e.g. methanol,ethylene-glycol, or propylene-glycol to operate, additional reactantwater polishing may be required to remove these compounds prior to usein the electrolysis process. The polishing may be accomplished by eithera additional device, or by the polisher 32.

A pump 30 is connected to the reactant water reservoir 22 by drain line23. The pump moves the water from the reservoir 22 to a water polisher32. Any type of water polisher 32 known in the art may be used to removecontaminants from the the reactant water. Preferably, the polisher 32will use a combination activated carbon/mixed resin ion exchange bed toremove any contaminants. After the reactant water is conditioned itmoves through check valve 34 into the electrolyzer cell 36.

Electrolyzer cell stack 36 comprises a plurality of cells similar tocell 100 described above with reference to FIG. 1 encapsulated withinsealed structures (not shown). The reactant water is received bymanifolds or other types of conduits (not shown) that are in fluidcommunication with the cell components. An electrical source compatiblewith a power source from the internal combustion engine is disposed inelectrical communication with each cell within cell stack 36 to providea driving force for the dissociation of the water.

Oxygen and water exit cell stack 36 via a common stream through valve 37and are separated in phase separator 38. Ultimately the water isreturned to the drain line 23, whereby the water is recycled and theoxygen is released to the atmosphere via vent 39. Optionally, the oxygenmay be returned back to the internal combustion engine to assist inenhancing combustion.

The hydrogen stream, which contains water, exits cell stack 36 and isfed to a phase separation/storage vessel 38, which acts as ahydrogen/water separation apparatus 44 and a storage vessel for holdingthe hydrogen until it is required by the internal combustion engine.Preferably, the vessel 38 is integral with the electrolyzer cell 36.However, the phase separation and storage may be accomplished byseparate devices and be located remote from the electrolyzer cell 36depending on the needs of the application. If a non-pressurized deviceis desired, the hydrogen can be stored as a solid, e.g., as a metalhydride, in a carbon based storage (e.g. particulates, nanofibers,nanotubes, or the like), and others, as well as combinations comprisingat least one of the foregoing storage forms. The storage capacity ispreferably at least 1 g of H₂ gas, but may be anywhere from 0.25 g toabout 10 g. This hydrogen stream has a pressure that is preferably about300 pounds per square inch (psi), but which may be anywhere from about 1psi to about 1000 psi. Some water is removed from the hydrogen stream atvessel 38 and may be returned to the electrolyzer via manifolds (notshown).

The hydrogen gas exits the vessel 38 through backpressure regulator 42and enters the internal combustion engine systems via line 46. A reliefvalve 44 is coupled to line 46 to vent H₂ gas to the atmosphere in theevent that pressure in line 46 reached undesirable levels.

All the valves, pumps and sensors are interfaced with a control system40. Control system 40 is a suitable electronic device capable ofaccepting data and instructions, executing the instructions to processthe data, and presenting the results. Therefore, control system 40 canbe a microprocessor, microcomputer, a minicomputer, an optical computer,a board computer, a complex instruction set computer, an ASIC(application specific integrated circuit), a reduced instruction setcomputer, an analog computer, a digital computer, a molecular computer,a quantum computer, a cellular computer, a superconducting computer, asupercomputer, a solid-state computer, a single-board computer, abuffered computer, a computer network, a desktop computer, a laptopcomputer, a scientific computer, a scientific calculator, or a hybrid ofany of the foregoing.

In addition to being coupled to one or more components within system 10,control system 40 may also be coupled to external computer networks suchas a Vehicle control system or an engine emission control system. Theseexternal systems are configured to communicate with control system 40using a well-known computer communications protocol such as TCP/IP(Transmission Control Protocol/Internet Protocol), RS-232, ModBus, andthe like.

During operation, the exhaust from the internal combustion engine isrouted through the pipe 13 and the venturi 14. Due to well knownpressure effects of the venturi, a low pressure zone is created at thebeginning of the venturi. Since return line 26 is coupled to the venturiat this low pressure zone, the pressure differential will cause gas toflow through line 15 either from the air inlet 16 or the exhaust pipeupstream from the venturi. While the exhaust gas may have a consistanthumidity level, typically 3% relative humidity (R.H.), the ambient airmay vary from as low as 10% R.H. to as high as 100% R.H. Since ambientair may have a higher moisture content than the exhaust gases, it ispreferable to have the dew point sensor 25 detect the R.H. humidity ofthe ambient air and have the control system determine when it wouldrequire less condenser energy to condensate water vapor from the ambientair instead of the exhaust. Once the appropriate source has beendetermined, the valve 27 is actuated to flow either exhaust gas orambient air into the condenser 18. Water which is removed from the airor exhaust is then stored in the reservoir 22 until it is needed by theelectrolysis cell 36. As the hydrogen is depleted from the vessel 38,additional reactant water is drawn by the pump 30 through the polisher32 and into the electrolysis cell 36. The check valve 34 is provided toprevent back flow of the water from the electrolysis cell 36 into thepolisher.

In the electrolysis cell 36, hydrogen and oxygen are disassociated. Thehydrogen flows into the vessel 38 replenishing the hydrogen used by theengine and the water oxygen combination exit the cell 36 through valve37 to a phase separator. The valve 37 which is operated by the controlsystem 40 is opened and closed to maintain the appropriate water levelinside the cell. The oxygen gas is removed from the water and release tothe atmosphere via vent 39. The excess water returns via line 41 to berecycled through the pump 30 and polisher 32.

As hydrogen gas is required by the internal combustion engine, theregulator releases hydrogen for use by the engine via line 46.Preferably the engine will consume hydrogen at a rate of at least 1.1mg/sec at 300 psi.

While preferred embodiments have been shown and described, variousmodifications and substitutions may be made thereto without departingfrom the spirit and scope of the invention. Accordingly, it is to beunderstood that the present invention has been described by way ofillustrations and not limitation.

1. A system for generating hydrogen for use with an internal combustionengine, the system comprising: an exhaust venturi; a condenser in fluidcommunication with said venturi and said air inlet, said condenserextracting water from said ambient air; an air inlet between saidventuri and condenser; and, an electrolyzer in fluid communication withsaid condenser, said electrolyzer producing hydrogen gas.
 2. Thehydrogen generating system of claim 1 further comprising a reservoir,said reservoir being in fluid communication with said condenser and saidventuri.
 3. The hydrogen generating system of claim 2 further comprisinga polisher, said polisher in fluid communication with said reservoir andsaid electrolyzer.
 4. A system for generating hydrogen for use with aninternal combustion engine, the system comprising: a means for removinga portion of an exhaust gas; a means for condensating water from saidexhaust gas; a means for storing said condensated water, said storagemeans coupled to said said condensating means; a means for electrolyzingsaid stored condensate water; a means for storing said hydrogen gas; agas inlet means, said gas inlet means including an ambient air inlet andan exhaust inlet; and, a means for determining the required condenserenergy, said determining means coupled to said inlet means.
 5. A systemfor generating hydrogen for use with an internal combustion engine, thesystem comprising: a means for removing a portion of an exhaust gas; ameans for condensating water from said exhaust gas; a means for storingsaid condensated water, said storage means coupled to said saidcondensating means; a means for electrolyzing said stored condensatewater; a means for storing said hydrogen gas; and, a means for providinga reserve reservoir.